Oil Industry Flowmeters
Accurate Positive Displacement Meters
Hazardous Area Readouts + Output
Chemical injection metering - topsides
VFF Series for 520 bar to ASME B31.3 code shown
Chemical Injection Flow Measurement & Control
Chemical injection fluids are normally viscous and are therefore natural applications for the VFF meter. The flowrates are relatively low and the pressure is high compared to most general industrial applications. The VFF Rotary meter is the ideal measuring element for these service requirements. Long term stability of metering and reliability is assured by the basic simplicity of design and quality of production.
VFF Meter Design & Advantages
The heart of the VFF meter is a simple but precisely made, oscillating rotor that sits freely within the rotor chamber of the meter. It is manufactured in a variety of materials. The meter principle is of 'positive displacement'. The rotor is driven 'positively' by the flow, which passes through the flowmeter in 'discrete pockets' with minimum fluid 'slippage'. This gives inherently greater accuracy than is available from axial flow turbine type meters for a low flow of a fluid more viscous than water. Each meter provides a exceptionally wide flowrange and has excellent low flow metering capability.
Screwed & Flanged Fitting
Meters have threaded entries for either NPT or Medium Pressure 1380 bar 20,000 psi tubing fittings or higher rated connections. Alternatively, they are available in flange fitting style for ANSI RF/RTJ. Even the higher pressure API 6BX (to 1380 bar) flanges or hub connectors may be specified. For installation, no straight pipe lengths are required and the line size can be varied directly at the flowmeter connections.
Meter Top Housing
The reed-switch sensor system is housed in a certified IP68 enclosure rated to 20m submersion and dust-tight. It provides a top or side mounting M20 gland connection for field cabling or alternatively for the mounting of a read-out instrument.
Intrinsically Safe
The VFF meter output is a 2-wire system providing a volt-free contact closure suitable for local instruments or transmission to a safe area. The output is considered 'simple apparatus' and is covered under European standards by clause 1.3 of EN50 014 and BS 5501: Part 1 as suitable for up to EEx ia IIc T4 class installations. The 2-wire connection to the safe area is isolated by a zener barrier or galvanic isolator device. If required a galvanic isolator is available which transposes the pulse output to a 4-20mA linear analogue 2-wire flowrate output signal. Alternatively, the meter output can be provided to an intrinsically safe local read- out instrument or Exd enclosed instrumentation in the hazardous area.
Approval to ASME B31.3
Lloyds Register provide accreditation of the VFF meter designs to the pressure vessel code ASME B31.3 as required. Compliance with this standard for flowmeters is a demand of many major companies in the Oil Industry.
Well Valve Position Monitoring & Leakage Detection
Well control valve actuators are of small volume and are stroked slowly to avoid shocks. Confirmation of actuator displacement is of vital operational interest. The VFF Rotary meter completely achieves this objective. The positive displacement principle assures 1% accuracy in nearly all circumstances.
The VFF meter is symmetrical for both forward and return flows. A 1% accuracy is normally achieved with a single 'bi-directional' calibration factor including for other effects of flowrate and viscosity variation. Simply counting the meter output pulses gives verification that the actuator has opened or closed correctly. Continuous pulses indicate line or actuator leakage.
For the detection of leaks in well control lines the VFF Meter is ideal. It has a wide flow capability and typically offers 'leak detection' starting from 5 to 15 ml/min. For high viscosity fluids, leaks from 0.5 ml/min can be sensed. The meter is inherently robust, meters with brass rotors have been tested with repeated blowdown of 600 bar to atmospheric pressure without damage.
High flowrate meters are used for applications such as the detection of umbilical line losses.
VFF Series for 520 bar & 690 bar to ASME B31.3
With I.S. Rate and Total Readout ? Battery Powered
Self-Powered Readouts
The VFF meter is available as an intrinsically safe, battery powered stand- alone system, equipped with flowrate and totaliser indicator. Battery exchange is made without calibration memory loss. This is CENELEC certified EEx ia IIB T4.
Powered Instrument Systems
The battery powered stand-alone system can be equipped with a loop-powered 4-20mA flowrate output. When installed in this way the unit becomes powered by the loop with the battery function supporting the unit as a standby.
VFF Meters with Flowrate Outputs
The battery powered stand-alone system with an intrinsically safe flowrate and totaliser indicator, can be equipped with a loop-powered 4-20mA flowrate output. The output is directly linear and proportional with flowrate.
Modular VFF Meters
For some meter constructions it is desirable to have an individual measurement module. Shown below is a wafer fitting, between-flange mounting flowmeter where a modular design allows a reduction in overall size and weight. An alternative wafer mounting type can be provided where the users flanges are bolted onto each side of the meter avoiding the use of tie- bolts. A high pressure meter is shown (right) where selection of a module can be made for specific needs.
Pic 1) Wafer fitting for 1": flanges 2500lb RTJ
Pic 2) VFF Series 2068 bar version with measuring module
Chemical injection metering - subsea
VFF Series meter illustrated is for 690 bar service pressure
and up to 1000m submersion
VFF Rotary Meters
The VFF Series Rotary Piston Meters are easily adapted for subsea chemical injection measurement. Their inherent reliability meets the low maintenance requirements of subsea service. Line pressures of 2068 bar, 30,000 psi can be currently met and higher pressures are possible. The maximum installation depth is only limited by the cabling connectors of the pressure-proof housing with its signal processing PCB. The PCB converts pulses from the sensor to a 4-20mA linear flowrate signal on a 2-wire output. The low power consumption allows the system to be loop-powered by the signal circuit as it needs less than 4mA.
In subsea versions two sensors are fitted. The electronics automatically searches for a working one to use after a flow stoppage, loop disconnection or sensor problem.
The meter output is monitored directly by an ROV by plugging into the meter connector or via submarine cabling to a remote location. Using this vital information of actual flowrate the chemical injection flow control valves can be set correctly and in a cabled installation continuous on-line chemical injection monitoring is achieved.
Helical Screw Meters
3" & 2" Wafer fitting type
for 690 bar API 6BX flanges to ASME B31.3
Precision metering of fuels - shipboard and offshore
Bi-directional metering of valve actuator hydraulic lines
Leak detection for umbilicals - wide range allows both large flows and very low leakage rates to be measured
Chemical injection metering of high flowrates
Pressures to 1034 bar. Intrinsically Safe
The positive displacement, high pressure Helical Screw Flowmeter is superior to axial flow turbine meters for the measurement of viscous fluids. It is ideal for the precision measurement of fuels, hydraulic fluids and chemical injection.
The meters are extensively used for the metering of fuels in marine environments. They accept fluid viscosity change and retain very high measurement accuracy. They are extremely robust and reliable.
For off-shore umbilical lines, flowrates from 0.1 to 350 l/min are available. Each meter offers a wide flowrate range allowing the detection and metering of leakage flows.
Typical applications of chemical injections are: MEG (mono-ethylene glycol), PAO (poly-alphaolefin) and DEG (di-ethylene glycol) for chemical injection to gas lines.
The Meters have been used for permanent installations and temporary test purposes for the 'foot-printing' of valve actuator movement.
Our Products
VFF Rotary Piston
LMX Pelton Wheel
Sierra Mass Gas Flowmeter
Helical Screw